File.



lJNlTED sratr nsrnrnnr onision OLIVER G. sinuous, or NAR'BERTH, PENNSYLVANIA, ASSIGNOR OF ONE-HALF T0 WILLIAM F. rzscninn, or PHILADELPHIA, PENNSYLVANIA.

FILE.

LOGELOTS,

To all whom it may concern;

Be it known that I, OLivnu Gr. SIMMQNS, a citizen of the United States, and. a rest dent of Narberth, in the county of Montgomery and State of Pennsylvania, have invented a new and Improved File, of which the following is a full, clear, and exact description.

This invention relates to metal Working tools and has particular reference to an improved manner of cutting edged tools such as files whereby the tiles are more rapid in cutting operation and more durable than files heretofore constructed.

Among the objects of this invention, therefore, is to produce by improved means a tile having milled teeth as distinguished from one in which the teeth are cut by a punching operation.

A further object of this invention is to provide a file having generated teeth, the teeth being so cut by a rotary milling cutter so as to provide the maximum amount of undercut Without destroying the proper effective form of the face of the file having the teeth.

The foregoing and other objects of this invention will hereinafter be more fully described and claimed and illustrated in the drawings forming a part of this specificai tion in which like characters of reference indicate corresponding parts in all the views, and in which-- Figure 1 is a plan View of a file representinn the same during the rocess cit cuttin t4 o C and showing by a dotted line a suggested form and position of: the cutting edge oi: the milling cutter which may be used in producing this file; Fig. 2 is a partial plan vie.

of the sarne on a larger scale; Fig. 3 is a vertical longitudinal section at a detail substantially on the line 3--3 oi Fig. 2, show-Q Specification of Letters Patent.

Application filed January '2, 1913.

ing in cross section a preferred forin of the? Patented May 27,1913.

Serial No. 740,598.

shown a spiral. Any suitable means may be employed to form these teeth, but I preier to use for this purpose a rotary milling cutter of the nature set forth in detail in my copending application, Serial No, 7%,599 filed of even date herewith. Sallie; it to say for purposes of this specification that-the said cutter is provided withga so ries of teeth arranged preferably in a spiral;

as shown at 12 in Fig. 1. It will be understood that the face of the cutter from which the cutting'teeth project will. occupy subst antially the position indicated by the line f in Fig. 3 with respect to the file teeth. While I do not wish to be limited to the form oi the curve or spiral, I prefer to use a cutter provided with an arrangement of cutting teeth the spirality or eccentricity of the curve being equal to the space be tween adjacent teeth of the file. as shown in Fig". 1. By the use of a cutter of the nature indicated, the file teeth are cut by a contii'iuous cutting contact of the cutter teeth upon the tile blanln the axis of the cutter being: inclined to the perpendicular to the tile at an angle substantially correspondine to the angle (10f, Fig. 3. and the spindle which carries the cutter being maintained by any suitable means at substantially fixed distance from the file blank; that is to say. with the cutter operating in the oirection of the arrow :1, the same spiral set ofcutting teeth will be operating simultaneously upon a plurality of tile teeth, it

being understood that there will be a rela tive movement between the axis oi the cut ter spindle and the tile blank represented by the arrow 7 While the spiral indicated in F l representing the arrangement of the cutting teeth of the milling cutter is shown as being of a single thread. it is to be understood that the principle of operation and the character of the file teeth would not be materially different if the cutter were to be arranged with a plu'nlity of parallel spirals. It is to be noted also tiat the axis of the cutter, while being suggested in Fig l as being to one side of the imaginary plane perpendicular to the tile blank and coinciding with the axis of the file, whereby the teeth at one edge of the face of the file are caused to be cut more nearly at right angles to the of the tilethan those on the op posite side, the principle of the invention would not be altered if the axis of the cutter were to be shifted toward or beyond said perpendicular plane. In all forms of the invention, however, and in the practical operations of thecutter, the centers of curvature of the file-teeth are all outside of the file, either within the plane indicated by the line f or'more remote from the face of the file. In other words, the curved cutting edges of the teeth all lie in the plane of the face of the file and the centers of curvature thereof lie outside of such plane, z. 6., beyond said plane from the file body. The advance or cutting face of each tooth, moreover, being undercut, forms an acute angle with the axis of curvature of its cutting edge.

As herein set forth, I prefer to arrange and shape the teeth so that there will be more inclination or slope to the teeth on one side of the file than on the other, andby virtue of the spiral action of the cutter, the teeth are so formed as to provide on each of them an outside face i which is bounded by the front cutting edge 0 and by the rear edge h, the outer face 2' being inclined downwardly or inwardly from the face a of the file preferably at an angle, indicated by. doc. Each tooth also has a front face 0, constituting the undercut above referred to, the angle of the undercut Z700 being greater than the angle of inclination of the cutter spindle aof. I also form each tooth with a rear face e forming the angle chd with the plane of the face 2'. This forn provides the maximum strength and cutting effect for the tooth and also provides awide clearance be tween adjacent teeth for the free exit of cuttings. The face i therefore is tapered by virtue of the fact that the lines 0 and h converge toward each other at their end which has the grelateririclination with respect to the axis of the tile. The drawings, however, show this feature to a very much exaggerated extent. As shown, therefore, in Figs. 3 and 4, the rear or inclined end of the face i is not only narrower than the other end, but the space'between teeth is wider and the groove shallower.

A file having milled teeth as herein set forth is much more satisfactory in practice than the common but file for the obvious the milling operation forms such cutting edges of a smooth and chisel-like form as distinguished from the metal in a cut file which is'struck up by the usual punching or chiseling operation and the molecules thereof are crystallized and left in a more or curves being spiral.

less ragged form, whereby they are soon worm out and the file consequently rendered useless.

As indicated in Fig. 5, a file cut in the manner set forth will have its cutting face substantially flat due to the fact that the inclination of the cutter spindle is so slight with respect to the normal to the face a. \V hen, however, it is desired to produce a file having a concave face, as indicated in Fig. 6, it may be produced simply by giving enough more inclination to the cutter axis as -to cause the portion of the file face between the lateral edges to be scooped out for this purpose. Files having concave faces are used to advantage in operating upon convex surfaces such as bolt or rivet heads, hand wheels or the like.

I am aware thatit is old to cut file teeth in the form of arcs or segments of circles in various arrangements on the face of the file,'and also that rat tail files have.

been proposed having several series of straight teeth out upon spiral lines extending from one end of the file to the other, but it is to benoted that the novel features ofmy .file hereinafter claimed are distinctly different from all such prior devices, with respect especially to the undercut and the outside face clearance above referred to, whereby the teeth are not'only very rapid for their purpose but may readily be resharpened.

Having thus described my invention, I claim as new and desire to secure by Let ters Patent 2 1. A file having spiral undercut teeth. 2. A file having teeth, each of which has an outer face bounded by two curves converging transversely of the file, one of such teeth each of 3. A file having undercut face tapered transversely which has an outer of the file. I

4. A substantially flat face cutting tool having a series of curved teeth, each tooth having a smooth milled sharp cutting edge lying in the plane of said face, the center of. curvature being outside of said plane, and the cutting face of each tooth being undercut forming an acute. angle with the axis of curvature of the cutting edge thereof. reason that the metal constituting the cutting edge of these teeth is not" disturbed and In testimony ,whereof I have signed my OLIVER G. SIMMONS.

Witnesses:

WM. M. LAKE, A. SCHRIVER. 

